1. Technical Field
The present disclosure relates to seals, and in particular, to seals that are adapted to seal doors such as semi-trailer trucks, boxcars, shipping containers, building doors, etc.
2. Description of Related Art
Known seals for use on, for example, the doors of semi-trailer trucks are made from a thermoplastic that is not able to withstand extreme hot or cold temperatures. Usually, such seals are used for only one or two seasons before seal replacement is needed. Thus, such known seals are short-term in use.
Some known seals are formed as a plurality of separate pieces that are not joined to one another. These separate members can be joined at their respective corners using separate molded corner blocks that must be sealed to the separate members via glue or silicone caulk, for example. Not only are these multi-piece seals expensive, the multi-piece seals are also difficult to install and maintain.
Further, some known thermoplastic seals rely on a flap that seals via bending against the rear frame of a trailer. However, thermoplastic has poor performance in compression set, which is the measure of the material's ability to maintain deformation force over a long period of time. Therefore, over time, the thermoplastic flap of the known seal will not maintain a sealing force against the frame of a semi-trailer truck.
Still other seals are pre-formed to fit a given truck door size. These seals normally cannot be deformed without compromising the effectiveness of the seal, and are therefore shipped as a single, door-shaped piece in a large, flat shipping container having approximately the same dimensions as the door to which the seal will be mounted.
A need exists for a new seal design that has an improved compression set performance and that may withstand extreme seasonal temperature changes to reduce the need for replacement of the seal after a short period of use.